1. Field of the Invention
The present invention relates to door hardware and, more particularly, a door handle attachment fixture that attaches a door handle to an escutcheon.
2. Description of the Background
In the door hardware industry, a common method of attaching a door handle to a mounting plate (or escutcheon) is to extend the hub of a door handle through an aperture in an escutcheon and then attach a C-clip or a retainer clip around the shank, securing the handle to the escutcheon. For example, FIG. 1 is a perspective view of the prior art showing the hub 14 of the door handle inserted through an aperture in an escutcheon 11, and a shank 10 inserted into the hub 14. The hub 14 protrudes up through a washer 13, and a C-clip 12 is affixed about the hub 14 to retain the door handle, effectively securing the handle to the escutcheon 11. Using a C-clip or other form of retainer clip has two major disadvantages. First, to achieve the desired fit and feel of the door handle, all components must have tight tolerances, and this increases the cost of manufacturing. Wide tolerances can cause overly loose or tight door handle function. Second, C-clips or like retainers afford only marginal structural strength, and can result in excessive cyclic wear.
Other attachment fixtures have been attempted.
For example, United States Patent Application No. 2008/0111384 by Ellis published May 15, 2008, discloses an apparatus for retaining a spring and spindle in the shank of a door handle using a torsion spring and retainer ring.
U.S. Pat. No. 7,347,462 to Ellis et al. issued Mar. 25, 2008, discloses a door handle assembly in which the shank of the door handle extends through the aperture of the mounting plate and through two attached bearings. A retainer device, such as a push retainer, a snap ring, or a nut, secures the door handle to the mounting plate.
U.S. Pat. No. 7,188,873 to Brown et al. issued Mar. 23, 2007, discloses a door handle system with a removable locking fastener comprising a nut and a star washer having nubs that engage a groove in the handle. This door handle system, however, does not allow for precise adjustment, and the ears on the fastener must be bent to secure the nut.
U.S. Pat. No. 6,997,024 to Etlicher issued Feb. 14, 2006, discloses a pull door lock in which the shank is retained in the escutcheon plate by engaging a C-clip with a groove at the end of the shank.
U.S. Pat. No. 4,784,418 to Pearson et al. issued Nov. 15, 1988, discloses a door latch handle fitting. To secure the lever handle to the mounting plate, the shank of the lever handle is positioned through the aperture of the mounting plate, and the retainer is pressed onto the shank portion, engaging the gripping tongues with the shank.
U.S. Pat. No. 4,343,502 to Nelson issued Aug. 10, 1982, discloses a doorknob construction in which an externally threaded end of the door handle is inserted through an aperture in the mounting rose, and the door handle is secured by an adjustment bushing nut.
U.S. Pat. No. 4,042,268 to Coglan issued Aug. 16, 1977, discloses a latch or lock set in which the lever is retained to the back plate by slipping a retaining spring over the barrel into two groves on the barrel.
None of the foregoing references fully address the current problem, and instead of affixing a C-clip at a fixed position along the door lever hub, it would be greatly advantageous to provide an adjustable fixture with improved wear resistance and compact size, that can be adjusted and semi-permanently installed in the field.